Please let me refer you to a document written by Mr. Gaskins on 23 June 2001 at http://www.concertina.info/tina.faq/conc-ap1a.htm An extract from that document states:
“On the train back from Stowmarket to London, I quickly noted down the APPROXIMATE years of various serial-ranges. (The dates are actually intermixed at year-breaks, as throughout all the ledgers, so it is NOT possible from this table to positively assign an instrument to a definite year--and my assignment of breaks is not necessarily any better than that of the manuscript note.) I added at the top the dates from the manuscript note, to give myself a complete list, though very rough:
1937-39: 50001-51134 [use manuscript note for 1937-1952]
1940-41: 51135-51432
1946-47: 51433-52216
1948-50: 52217-53688 [53689 - 53699 missing?]
1951: 53700-54449
1952: 54450-55338
1953: 55339-56448 [55339-56390 note; 55492-56448 ledger]”
I have dated concertinas on my list according to these APPROXIMATE dates. It seems not to be as accurate as I’ve hoped for. I believe that this discovery will bring all of us closer to more accurate dating.
The concertina in question was inherited by Dr. Louis Adendorff, a well respected citizen, from his late father. Dr. Adendorff assured me that his father told him that he bought the concertina one year before Dr. Adendorff’s birth, being in 1948. I do not have any reason to doubt these facts. In short: Concertina nr 53120 was in the possession of the Adendorff family in South Africa in 1947 and never left South Africa.
Numbers were changed when instruments were returned for repairs. It did not happen in this case. I am not convinced that the changing of numbers as applied in the 1890’s, can be offered as a solution in this instance.
The receipt offered as evidence of accuracy of Mr. Minting's list dates back to 1941. It proves that concertina 51406 was sold on 26th September 1941. It does not prove the accuracy of Mr. Minting’s list. It would have been helpful to have something similar for 1947.